JPH04265543A - Substrate for optical disk - Google Patents

Abstract

PURPOSE:To suppress defective products during the continuous formation of a 2P layer and to obtain good adhesion strength between the substrate and the 2P layer at high temp. and high humidity. CONSTITUTION:The optical disk substrate consists of a glass substrate, a primer layer and a 2P layer. The primer layer consists of a primer layer material (1) containing titanate coupling agent, acrylic acid ester and photopolymn. initiator. The 2P layer has a rugged pattern for guide grooves and/or signal pits and consists of a photosetting resin comspn. (2).

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is directed to the production of 2P (Photo Polymeriz) on an optically transparent glass substrate.
photocurable resin (Pho cation) method.
to Polymer, hereinafter referred to as 2P resin. ) consisting of a guide groove and/or a concavo-convex pattern of a signal bit (hereinafter referred to as
This is called the 2P layer. ), and more specifically, the present invention relates to an optical disc substrate having excellent adhesiveness between a glass substrate and a 2P layer.

0002

[Prior Art] Three types of optical discs are known: read-only type, write-once type, and rewritable type, and read-only type and write-once type optical disks are already used in various fields. . The development of rewritable optical disks is also progressing rapidly, and magneto-optical disks in particular are about to enter the period of full-scale practical use.

[0003] As substrate materials for these optical discs, thermoplastic resins such as polymethyl methacrylate and polycarbonate, thermosetting resins such as epoxy resins, or glass are generally used. In addition, active research is also being conducted on new polyolefin resins that have characteristics such as low birefringence and low water absorption, especially as substrate materials for magneto-optical disks.

Nowadays, when it is necessary to transmit, process, and store a wide variety of enormous amounts of information, the performance required of optical disks as recording media is large capacity, high speed data transfer, and high reliability. The main focus of research is on these points. In order to achieve these advanced performances, the role played by the substrate material is extremely important.
In this sense, great expectations are placed on glass substrates.

For example, increasing capacity can be achieved by increasing the diameter of the substrate, but with polycarbonate substrates, which are currently the most commonly used, when the diameter is about 300 mm, mechanical properties such as surface runout occur when the disk rotates. This results in deterioration, making it difficult to cope with high-speed rotation (3600 rpm or more). In addition, it is difficult to control injection molding conditions,
There are drawbacks such as an increase in birefringence distribution in the circumferential direction. In this respect, glass is a substrate material with the best mechanical properties, and is advantageous for increasing the diameter without birefringence.

[0006] Furthermore, in order to speed up data transfer, research is being conducted to increase the disk rotation speed.
Recently, experiments have been conducted on high-speed recording of 5000 rpm or more. In this respect as well, glass substrates have much better dynamic mechanical properties than other plastic substrates, and glass substrates can be said to be optimal for high rotational speed recording.

Furthermore, glass substrates are excellent in stability under high temperature and high humidity conditions, and are the most reliable substrate material.

[0008] Generally, an uneven pattern such as a guide groove for guiding a laser beam or a preformat signal pit is formed in advance on an optical disk substrate, but in the case of a glass substrate, an uneven pattern is formed using 2P resin. The 2P method is known.

However, even if the 2P resin, which is an organic material, is directly formed on the glass, which is an inorganic material, a large adhesion force cannot be obtained between the two, resulting in the following disadvantages.

[0010] That is, during 2P molding, when the glass substrate is peeled off from the stamper (a molding die created by transferring from the master by electroforming), some or all of the hardened 2P resin remains on the stamper side. Otherwise, floating (an air space formed between the glass substrate and the 2P layer) frequently occurs in a part of the 2P layer formed on the glass substrate. In addition, even if the 2P molding is in good condition, cracks, wrinkles, and flakes will occur over time under high temperature and high humidity conditions.

In order to improve the above-mentioned problems, various studies have been made to improve the adhesive strength between glass and 2P resin. The most widely known method among these studies is to form a coating film of a primer made by diluting various silane coupling agents with an organic solvent on a glass substrate, and the following examples have been reported in the past. has been done.

For example, JP-A-62-139150 discloses that by providing an aminosilane primer layer diluted with toluene between a glass substrate and an epoxy resin layer, the adhesive strength between the two can be increased. Are listed.

In addition, JP-A-59-65953 discloses that a silane coupling agent having an acrylic group or a methacryl group is used, and an aromatic hydrocarbon, ether type, or ketone type with a boiling point of 120 to 200°C is used. , ester type,
It is described that a primer composition diluted with at least one type of polyhydric alcohol ester solvent and further added with an organic acid is effective.

Furthermore, JP-A-1-248335 also describes an example in which a primer composition in which ethene-based unsaturated silane is diluted with methyl alcohol is effective.

[0015]

[Problems to be Solved by the Invention] All of the conventional methods described above are effective to some extent in improving the adhesiveness between the glass substrate and the 2P resin. However, when continuous 2P molding is performed using a 2P resin that has excellent moldability, that is, good flowability (700 cps, 25°C or less) and good releasability from the stamper after curing, floating occurs partially. Peeling test (JIS, K5400,
8.52, Species Standard), defective products with a residual film rate ({total square area - peeling area} ÷ total square area) of 90% or less may be produced. These problems arise from insufficient initial adhesion between the glass substrate and the 2P resin.

Furthermore, due to this weak initial adhesive strength, minute undulations occur in the 2P layer when it is peeled off from the stamper, so that the axial acceleration exceeds the standard (20 m/sec2 or more).
In some cases, defective products may occur.

Furthermore, even if the initial adhesive strength is good, cracks, wrinkles, and flakes may occur over time under high temperature and high humidity conditions (eg, 80° C., 85% RH).

As described above, in the conventional method of performing primer treatment on the glass substrate, the glass substrate and the 2P
There was a problem in that the adhesive strength between the resin and the resin was insufficient, resulting in a high incidence of defective products during continuous molding.

The problem to be solved by the present invention is to increase the adhesive strength between the glass substrate and the 2P layer of an optical disc substrate in which a 2P layer made of 2P resin is provided on a glass substrate, and to improve the continuity of the 2P method. The incidence of defective products during molding is low,
It is an object of the present invention to provide a highly reliable substrate for an optical disk in which the adhesive strength between a glass substrate and a 2P layer does not decrease even when kept in high temperature and high humidity for a long time.

[0020]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides guide grooves and/or signal bits made of (1) a primer layer and (2) a photocurable resin composition on a glass substrate. In an optical disc substrate having a concavo-convex pattern, the primer layer contains a titanate coupling agent,
Provided is a substrate for an optical disc, characterized in that it is a cured layer made of a primer layer constituent material containing an acrylic acid ester and a photopolymerization initiator.

FIG. 1 is a sectional view of an optical disk substrate according to the present invention. In this figure, 1 is a disk-shaped glass substrate, 2 is a primer layer made of a cured mixture of an alkoxysilane having a methacrylic group, an acrylic acid ester, and a photopolymerization initiator, and 3 is a 2P layer.

As the glass substrate 1, glass such as chemically strengthened soda lime glass or soda aluminosilicate glass is suitable, and a disk-shaped glass is used.

The glass substrate is cleaned immediately before forming the primer layer 2 in order to remove organic matter or dust adhering to the surface. Effective cleaning methods include scrub cleaning in pure water and detergent, ultrapure water cleaning, etc. using a 4 to 8 continuous automatic cleaning device. By performing this cleaning, organic substances, dust, etc. on the surface of the glass substrate are removed. This pretreatment allows the primer layer 2 to be uniformly applied onto the glass substrate, and eliminates unevenness in the adhesive force of the 2P layer 3 to the glass.

For the primer layer 2, a primer layer constituent material containing a titanate coupling agent, an acrylic ester, and a photopolymerization initiator is applied, the acrylic ester is cured by irradiation with ultraviolet rays, and then baked. formed by

[0025] As the titanate coupling agent used in the present invention, for example, formula (1)

[0026]

[Chemical formula 1]

Isopropyl triisostearoyl titanate, represented by the formula

[0028]

[Case 2]

A monoalkoxy type having an isopropoxy group as a hydrophilic group such as isopropyl tris(dioctylpyrophosphate) titanate represented by
2) Formula

[0030]

[Chemical formula 3]

A chelate type having an oxyacetic acid residue as a hydrophilic group such as bis(dioctylpyrophosphate)oxyacetate titanate represented by the formula (3);

[0032]

[C4]

Examples include chelate types having an ethylene glycol residue as a hydrophilic group, such as bis(dioctylpyrophosphate) ethylene titanate represented by the following.

These titanate coupling agents are:
Can be used alone or in combination of two or more,
The blending ratio in the primer layer constituent material is 0.1 to 10.
A range of 0% by weight is preferred.

Examples of the acrylic esters used in the present invention include polyester acrylates such as propylene oxide adipic acrylic acid and diethylene glycol acrylic trimetate; epoxy acrylates such as bisphenol A epichlorohydrin acrylic acid and phenol novolak epichlorohydrin acrylic acid;
Urethane acrylates such as ethylene glycol adipate tolylene diisocyanate 2-hydroxyethyl acrylate, polyethylene glycol tolylene diisocyanate 2-hydroxyethyl acrylate; monofunctional acrylate monomers such as 2-hydroxyethyl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate; diethylene glycol Diacrylate, neopentyl glycol diacrylate, 3
Examples include bifunctional acrylate monomers such as methylpentanediol diacrylate; trifunctional or higher functional acrylate monomers such as trimethylolpropane triacrylate, dipentaerythritol propionate tetraacrylate, and dipentaerythritol hexaacrylate.

These acrylic esters can be used alone or in combination of two or more.

The blending ratio of the titanate coupling agent in the primer layer forming material is preferably in the range of 0.1 to 10.0% by weight, and the blending ratio of the acrylic ester is 8% by weight.
The range is preferably from 5.0 to 99.8% by weight, and the blending ratio of the photopolymerization initiator is preferably from 0.1 to 5.0% by weight.

[0038] Furthermore, an organic solvent may be added for the purpose of improving the fluidity of the primer constituent material.

The organic solvent that can be added to the material constituting the primer layer is preferably one that forms a uniform solution and improves fluidity when mixed with the above-mentioned acrylic ester, and examples of such organic solvents include, for example. , aromatic hydrocarbons such as toluene, xylene, and benzene; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate and n-butyl acetate; alcohols such as ethyl alcohol and isopropyl alcohol.

These organic solvents can be used alone or in combination of two or more.

The primer layer can be formed by a known coating method such as a spin coating method, a dipping method, or a spray method, but the spin coating method is preferable because it is easy to mass-produce and forms a uniform coating film. Optimal. Furthermore, when forming a coating film by spin coating, the organic solvent in the primer can be dried by keeping the glass substrate rotating.

[0042] After applying the primer constituent material and curing the acrylic ester by irradiating it with ultraviolet rays, baking is performed. Baking is done in air at 100-200℃ for 10-60℃.
It is preferable to do this for about a minute.

The 2P layer 3 made of 2P resin is formed by the 2P method described below.

That is, on a stamper (a molding die made by transferring from a master by electroforming) on which a concavo-convex pattern such as a guide groove for guiding a laser beam and/or a preformat signal pit is formed, A glass substrate 1 is coated with liquid 2P resin, and the glass substrate 1 is placed so that the side on which the primer layer 2 made of a silane coupling agent is formed faces the stamper side, and pressure is applied to spread the uncured 2P resin. After curing the 2P resin by irradiating it with ultraviolet light from the side, it is peeled off from the stamper to form a 2P layer 3 having a desired uneven pattern.

2 used when forming the 2P layer of the present invention
Examples of the P resin include, for example, a photo-radical polymerization composition containing a photo-radical polymerizable prepolymer, a monomer, and a photo-radical polymerization initiator as main components; A photocationic polymerization composition as the main component; a composition that is cured by ultraviolet rays, such as a composition that is a mixture of a photoradical polymerization composition and a photocationic polymerization composition, and has good peelability from a stamper and transferability of uneven patterns after curing. It can be used without any particular restriction as long as it has good heat and humidity resistance.

[0046]

EXAMPLES The present invention will be explained in more detail below with reference to Examples and Comparative Examples.

(Example 1) Outer diameter 130 mm, inner diameter 15 m
A soda aluminosilicate glass substrate with a size of 1.1 mm and a thickness is subjected to scrub cleaning in pure water and detergent and ultrasonic cleaning in ultrapure water using a 5-pot automatic cleaning device. Organic substances and dust on the surface of the glass substrate were removed.

Within 30 minutes after washing, 1.0% by weight of isopropyl triisostearoyl titanate, 30.0% by weight of ethylene glycol adipate tolylene diisocyanate 2-hydroxyethyl acrylate, xylene 68
．． A primer layer constituent material consisting of a mixture of 0% by weight and 1.0% by weight of hydroxycyclohexyl phenylketone was applied onto a glass substrate by spin coating. For the primer layer constituent materials, predetermined amounts of ethylene glycol adipate tolylene diisocyanate 2-hydroxyethyl acrylate, xylene, and hydroxycyclohexylphenyl ketone are placed in a glass container, and while stirring under ice cooling, isopropyl triisostearoyl titanate is added. It was prepared by gradually dropping it.

[0049] Spin coating was performed under the following conditions. (Spin coating conditions) * Low speed rotation: 60 rpm, 14 seconds (Primer application time: 12 seconds) * High speed rotation:
After applying the primer layer constituent material and drying the solvent under the above conditions at 2800 rpm for 30 seconds, UV rays were applied for 30 seconds.
The material constituting the primer layer was cured by irradiation at 0 mW/cm2 for 20 seconds. Next, in a clean oven, 10
Baking treatment was performed at 0°C for 1 hour.

Continuous molding was performed on the primer layer forming surface of the glass substrate on which the primer layer was formed by the above method using a 2P molding machine (manufactured by Dainippon Ink and Chemicals).
A P layer was formed. In this case, "STM-401" (manufactured by Dainippon Ink and Chemicals) was used as the 2P resin forming the 2P layer.

All 50 glass substrates on which the 2P layer was formed were in good molding condition, and during 2P molding, when the glass substrate was peeled off from the stamper, some or all of the hardened 2P layer was on the stamper side. Nothing remains,
In addition, no air bubbles (an air layer formed between the glass substrate and the 2P layer) were generated in a part of the 2P layer formed on the glass substrate.

[0052] In order to evaluate the initial adhesive strength between the 2P layer and the glass substrate, a checkerboard peel test (JIS, D-20
2, 8.121 type standard), the remaining film rate was 100% on all 50 glass substrates.

[0053] Also, even after the heat and humidity test at 80°C, 85% RH, for 2000 hours, the results of the cross-cut peeling test were as follows.
The remaining film rate was 100% for all 50 glass substrates.
No cracks, wrinkles, or flakes were observed in the 2P layer.

(Example 2) In Example 1, the materials constituting the primer layer were 1.0% by weight of isopropyl triisostearoyl titanate, 35.0% by weight of bisphenol A-epichlorohydrin acrylic acid, and 3% by weight of xylene.
0.0% by weight, 33.0% by weight of methyl isobutyl ketone
A primer layer and a 2P layer were formed on the surface of a glass substrate in the same manner as in Example 1, except that a primer layer constituent material consisting of a mixture of 1.0% by weight of hydroxycyclohexylphenyl ketone and A similar evaluation was conducted.

As a result, the molding condition of all 50 glass substrates was good, and even in the grid peel test, the molding condition was good.
The remaining film rate was 100% for all glass substrates.

[0056] Also, even after the heat and humidity test at 80°C, 85% RH for 2000 hours, the results of the cross-cut peeling test were as follows.
The remaining film rate was 100% for all 50 glass substrates.
No cracks, wrinkles, or flakes were observed in the 2P layer on any of the substrates.

(Example 3) In Example 1, the primer layer constituent materials were 1.0% by weight of bis(dioctylpyrophosphate) ethylene titanate, 98.0% by weight of neopentyl glycol acrylate, and 1.0% by weight of hydroxycyclohexyl phenyl ketone. A primer layer and 2P were formed on the surface of a glass substrate in the same manner as in Example 1, except that a primer layer constituent material consisting of a mixture of % by weight was used.
A layer was formed and the same evaluation as in Example 1 was performed. As a result, all 50 glass substrates had good molding conditions, and even in the grid peel test, the remaining film rate was 100% for all 50 glass substrates.

[0058] Also, the result of the cross-cut peeling test after the heat and humidity test at 80°C, 85% RH for 2000 hours was 49.
The remaining film rate for two glass substrates is 100%, and one glass substrate has a remaining film rate of 90% or more and less than 100%, and no cracks, wrinkles, or flakes are observed on the 2P layer on all substrates. There wasn't.

(Comparative Example 1) In the same manner as in Example 1, except that the primer layer was not formed,
When the 2P layer was continuously formed on the surfaces of 10 glass substrates, most of the hardened 2P layer remained on the stamper side when the 2P layer was peeled off from the stamper in all the glass substrates.

(Comparative Example 2) In Example 1, a primer layer constituent material consisting of a mixed solution of 1.0% by weight γ-methacryloxypropyltrimethoxysilane and 99.0% by weight toluene was used. ,2
A primer layer and a 2P layer were formed on the surface of the glass substrate in the same manner as in Example 1, except that 0 substrates were used, and the same evaluation as in Example 1 was performed.

As a result, out of 20 glass substrates, 11 were in good molding condition, and 9 glass substrates were in good condition.
When peeling off from the stamper during 2P molding, the hardened 2P
Part of the layer remained on the stamper side.

In order to evaluate the initial adhesive strength between the 2P layer and the glass substrate, a grid peel test was conducted in the same manner as in Example 1, and the residual film rate was 20% for all 20 glass substrates.
It was below.

(Comparative Example 3) In Example 1, 1.0% of γ-methacryloxypropyltrimethoxysilane and 99.0% of n-butyl acetate were used as primer layer constituent materials.
Using a primer layer constituent material consisting of a mixed solution of 2.
A primer layer and a 2P layer were formed on the surface of the glass substrate in the same manner as in Example 1, except that 0 substrates were used, and the same evaluation as in Example 1 was performed.

As a result, out of 20 glass substrates, 13 were in good molding condition, and 7 glass substrates were in good condition.
When peeling off from the stamper during 2P molding, the hardened 2P
Part of the layer remained on the stamper side.

In order to evaluate the initial adhesive strength between the 2P layer and the glass substrate, a grid peel test was conducted in the same manner as in Example 1, and the residual film rate was 20% for all 20 glass substrates.
It was below.

(Comparative Example 4) In Example 1, 1.0% by weight of γ-methacryloxypropyltrimethoxysilane and 99% of methyl alcohol were used as primer layer constituent materials.
．． A primer layer and a 2P layer were formed on the glass substrate surface in the same manner as in Example 1, except that a primer layer constituent material consisting of a 0% by weight mixed solution was used, and the same evaluation as in Example 1 was performed. .

As a result, all 50 glass substrates were found to be in good molding condition.

In order to evaluate the initial adhesive strength between the 2P layer and the glass substrate, a grid peel test was conducted in the same manner as in Example 1, and 15 sheets had a residual film rate of 100%, and 28 sheets had no residual film. The rate is 90% or more and less than 100%, and 7 sheets have a residual film rate of 80.
% or more and less than 90%.

[0069] Also, the results of the cross-cut peeling test after the heat and humidity test at 80°C, 85% RH for 2000 hours were 35%.
13 sheets have a residual film rate of 80% or more and less than 90%, and 2 sheets have a residual film rate of 60%.
It was less than 70%. Furthermore, in 28 substrates, the occurrence of floating in the 2P layer was observed.

(Comparative Example 5) In Example 1, 1.0% by weight of γ-methacryloxypropyltrimethoxysilane and 99% of ethyl alcohol were used as primer layer constituent materials.
．． A primer layer and a 2P layer were formed on the glass substrate surface in the same manner as in Example 1, except that a primer layer constituent material consisting of a 0% by weight mixed solution was used, and the same evaluation as in Example 1 was performed. .

As a result, all 50 glass substrates were found to be in good molding condition. In order to evaluate the initial adhesive strength between the 2P layer and the glass substrate, a grid peel test was conducted in the same manner as in Example 1, and 18 sheets had a residual film rate of 100%, and 22 sheets had a residual film rate of 90%. or more and less than 100%,
Ten sheets had a residual film rate of 80% or more and less than 90%.

[0072] Also, the results of the cross-cut peeling test after the heat and humidity test at 80°C, 85% RH for 2000 hours were 33.
13 sheets have a residual film rate of 80% or more and less than 90%, and 4 sheets have a residual film rate of 60%.
It was less than 70%. Furthermore, in 31 substrates, the occurrence of floating in the 2P layer was observed.

(Comparative Example 6) In Example 1, 1.0% by weight of N-β-(aminoethyl)γ-aminopropyltrimethoxysilane and 99% water were used as primer layer constituent materials.
．． A primer layer and a 2P layer were formed on the glass substrate surface in the same manner as in Example 1, except that a primer layer constituent material consisting of a 0% by weight mixed solution was used, and the same evaluation as in Example 1 was performed. .

As a result, out of 50 glass substrates, 46 were in good molding condition, and 4 glass substrates were
When peeling off from the stamper during 2P molding, the hardened 2P
Part of the layer remained on the stamper side.

In order to evaluate the initial adhesive strength between the 2P layer and the glass substrate, a grid peel test was conducted in the same manner as in Example 1, and 8 sheets had a residual film rate of 80% or more and less than 90%.
Ten sheets had a residual film rate of 70% or more and less than 80%, and 32 sheets had a residual film rate of less than 70%.

[0076] Furthermore, the results of the cross-cut peeling test after the heat and humidity test at 80°C, 85% RH for 2000 hours were as follows:
The remaining film rate was 50% or less for all the glass substrates. Furthermore, in 28 substrates, the occurrence of floating in the 2P layer was observed.

(Comparative Example 7) In Example 1, a primer layer constituting material consisting of a mixed solution of 1.0% by weight of γ-aminopropyltriethoxysilane and 99.0% by weight of water was used. Other than that, Example 1
In the same manner as above, a primer layer and a second layer are formed on the surface of the glass substrate.
A P layer was formed and the same evaluation as in Example 1 was performed.

Among the 50 glass substrates, 42 were in good molding condition, and 8 glass substrates had a part of the hardened 2P layer on the stamper side when peeled from the stamper during 2P molding. It remained.

[0079] In order to evaluate the initial adhesive strength between the 2P layer and the glass substrate, a checkerboard Cellotape peeling test was conducted in the same manner as in Example 1, and 6 pieces had a residual film rate of 80% or more and less than 90%. Thirteen sheets had a residual film rate of 70% or more and less than 80%, and 31 sheets had a residual film rate of less than 70%.

[0080] In addition, the results of the cross-cut peeling test after the heat and humidity test at 80°C, 85% RH for 2000 hours were as follows:
The remaining film rate was 50% or less for all the glass substrates. Furthermore, in 36 substrates, the occurrence of floating in the 2P layer was observed.

(Comparative Example 8) In Example 1, the primer layer was composed of a mixed solution of 1.0% by weight N-phenyl-γ-aminopropyltrimethoxysilane and 99.0% by weight water. A primer layer and a 2P layer were formed on the surface of a glass substrate in the same manner as in Example 1, except that the materials were used, and the same evaluation as in Example 1 was performed.

Among the 50 glass substrates, 31 were in good molding condition, and 19 glass substrates had a part of the hardened 2P layer on the stamper side when peeled from the stamper during 2P molding. It remained.

[0083] In order to evaluate the initial adhesive strength between the 2P layer and the glass substrate, a checkerboard Cellotape peeling test was conducted in the same manner as in Example 1, and 6 pieces had a residual film rate of 70% or more and less than 80%. Ten sheets had a residual film rate of 60% or more and less than 70%, and 34 sheets had a residual film rate of less than 60%.

[0084] Also, the results of the cross-cut peeling test after the heat and humidity test at 80°C, 85% RH for 2000 hours were as follows:
The remaining film rate was 50% or less for all the glass substrates. Furthermore, in 50 substrates, the occurrence of floating in the 2P layer was observed.

(Comparative Example 9) In Example 1, a mixed solution of 1.0% by weight of γ-glycidoxypropyltrimethoxysilane, 99.0% by weight of water, and 0.1% by weight of acetic acid was used as the material constituting the primer layer. A primer layer and a 2P layer were formed on the surface of a glass substrate in the same manner as in Example 1, except that 20 substrates were used, and the same evaluation as in Example 1 was performed. Ta.

Among the 20 glass substrates, 7 were in good molding condition, and 13 glass substrates had a part of the hardened 2P layer on the stamper side when peeled from the stamper during 2P molding. It remained.

[0087] In order to evaluate the initial adhesion between the 2P layer and the glass substrate, a cross-cut Cellotape peeling test was conducted in the same manner as in Example 1, and the residual film rate was 20% for all 20 glass substrates. It was below.

(Comparative Example 10) In Example 1, the primer layer was composed of a mixed solution of 1.0% by weight of γ-mercaptopropyltrimethoxysilane, 99.0% by weight of water, and 0.1% by weight of acetic acid. A primer layer and a 2P layer were formed on the surface of a glass substrate in the same manner as in Example 1, except that the primer layer constituent material was used and 20 substrates were used, and the same evaluation as in Example 1 was performed.

Among the 20 glass substrates, 6 were in good molding condition, and 14 glass substrates had a part of the hardened 2P layer on the stamper side when peeled from the stamper during 2P molding. It remained.

[0090] In order to evaluate the initial adhesion between the 2P layer and the glass substrate, a cross-cut Cellotape peeling test was conducted in the same manner as in Example 1, and the residual film rate was 20% for all 20 glass substrates. It was below.

[0091]

Effects of the Invention The optical disc substrate of the present invention has a strong adhesive strength between the glass substrate and the 2P resin constituting the 2P layer, so the incidence of defective products during continuous molding using the 2P method is low, and it can withstand high temperatures and high humidity. In particular, since the adhesive strength between the glass substrate and the 2P layer does not decrease, it is possible to provide an optical disc substrate with high long-term reliability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the basic structure of an optical disc substrate of the present invention.

[Explanation of symbols]

1 Glass substrate 2 Primer layer 3 2P layer

Claims (3)

[Claims] 1. An optical disc substrate having, on a glass substrate, (1) a primer layer and (2) a concavo-convex pattern layer of guide grooves and/or signal pits made of a photocurable resin composition, wherein the primer layer is made of titanate. 1. A substrate for an optical disc, characterized in that the cured layer is made of a primer layer constituent material containing a coupling agent, an acrylic acid ester, and a photopolymerization initiator. [Claim 2] The titanate coupling agent is (1
) a monoalkoxy type having an isopropoxy group as a hydrophilic group, (2) a chelate type having an oxyacetic acid residue as a hydrophilic group, and (3) a chelate type having an ethylene glycol residue as a hydrophilic group. 2. The optical disc substrate according to claim 1, further comprising: 3. The blending ratio of the titanate coupling agent in the primer layer constituent material is in the range of 0.1 to 10.0% by weight, and the blending ratio of the acrylic ester is 85% by weight.
．． 1. A substrate for an optical disc, characterized in that the blending ratio of a photopolymerization initiator is in the range of 0 to 99.8% by weight and in the range of 0.1 to 5.0% by weight.